Receptacle for a programmable, electronic processing device

ABSTRACT

A mount for a programmable electronic processing device is disclosed. It is divided into at least a first functional unit ( 7 ) and a second functional unit ( 8 ) which represent separate, particularly monolithic integrated, components. The first functional unit ( 7 ) defines all input and output interfaces of the processing device with respect to their electrical properties. All essential connections of the second functional unit ( 8 ) are accessible from outside only via the first functional unit ( 7 ). To this end, the first functional unit ( 7 ) includes matching circuits which serve to electrically adapt the connections of the second functional unit ( 8 ) to the external conditions.

This invention relates to a mount in the sense of a package or an enclosure or a carrier device for a programmable electronic processing device. As a rule, such processing devices constitute a processor which comprises at least one monolithic integrated circuit. Both analog and digital signals or data are processed, depending on the application. The relatively small electronic modules allow these processors to be housed along with additional circuits, such as memories, in a relatively small package. Because of the small package dimensions, one also speaks of “microprocessors”. If at least two individual structures are contained in a mount, this is also referred to as a “hybrid circuit”, as distinguished from those cases where only a single monolithic integrated circuit is present.

The use of microprocessors is increasing in all areas of technology, since with their aid, control processes can be optimized. The additional cost and complexity is relatively low and allows decentralized solutions. A wide range of applications is in mechanical engineering, particularly in the automotive field, which is increasingly resorting to such microprocessors in order to optimize the behavior of the vehicle at various points.

In many cases where such processors can be used, however, a basic problem arises from the fact that the cycle times differ very widely for the manufacturer and the user of the processors. When such processors are adopted in a technical system, as uniform a product as possible should be available for the manufacture and for replacement throughout the development, planning, fabrication, and operating times of the associated system.

In the event of a technology change, aside from the changes in electrical connection parameters, the changed sensitivities to overvoltages, polarity reversals, and electromagnetic interference have to be taken into account. There are also changes in the interfering effect on other circuits, for instance by steeper clock-pulse and data edges which travel as electromagnetic interference signals over relatively long lines.

The development in semiconductor technology is generally ahead of the time frame specified by the user, because it must follow current technology changes so as to be able to implement increasingly complex circuits. The continued use of obsolete technologies involves the use of parallel production lines, which are usually uneconomical, because full capacity utilization is not ensured.

It is therefore an object of the invention characterized in claim 1 to provide a sgitable solution to the above problems which enables the semiconductor manufacturer, on the one hand, to use state-of-the-art semiconductor processes and, on the other hand, to offer the user a guarantee that a product is constant for a long time.

This object is attained by the teaching set forth in the characterizing part of claims 1. The mount according to the invention and the processing device are not be regarded as independent parts, but the mount is assigned a first functional unit of the processing device which essentially defines the external electrical conditions of the processing device. The processing proper takes place in a second functional unit, whose essential connections are normally accessible from outside only via the external connections of the first functional unit. The term “essential connections” as used herein includes those connections which, as seen from outside, are critical in terms of their electrical parameters because their tolerances are tight or because their active or passive disturbance behavior has to be taken into account. Uncritical connections, such as set or reset inputs, may be included but need not necessarily be routed via the first functional unit, even though this is safer in the long run in view of the foreseeable development of the technology used. The arrangement comprising a first and a second functional unit in a mount is similar to a hybrid circuit but serves an entirely different purpose. The first functional unit, which may also consist of more than one monolithic integrated circuit, serves essentially only to define the external conditions and make available suitable matching circuits for the second functional unit. In this manner, the processing device proper, which is contained in the second functional unit and may also consist of more than one monolithic integrated circuit, is “masked” as viewed from outside. In addition to the pure matching circuits, the first functional unit may contain subcircuits performing more general functions, such as oscillators, supply voltage regulator circuits, buffer circuits, protective circuits, etc. The supply voltage regulator circuits permit autonomous operation of the microprocessor in a supply system with an unregulated or excessive supply voltage. This is particularly important for the operation of the second functional unit, whose supply voltage must, if necessary, be adapted to the technology used, while, on the other hand, the original supply voltage must be retained for other electronic circuits or measuring devices. Since, as a rule, the processing device also contains memory devices, the write and erase voltages of the latter are also advantageously generated or adapted in the first functional unit.

The division into a first and a second functional unit allows a further technological development of the processing device proper without this having to be taken into account from outsidel provided that the technology is retained for the first functional unit. Further developments of the technology are generally associated with higher processing rates and lower voltage levels. Over the relatively long leads, the processing rates increase the interference potential to be taken into account. On the other hand, the higher processing rates permit sequential processing for many processes for which parallel processing was previously necessary because of the lower processing speed. Parallel processing generally necessitates parallel data inputs and outputs, whereby the number of contact pads, and thus the amount of chip area required, is increased. Thus, it is necessary despite the increasing functionality of the processors not to let the number of contact pads increase in proportion thereto, but to limit it. Accordingly, serial data input and output is desirable in the second functional unit. This, however, requires suitable conversion devices in the first functional unit.

If the matching circuits are not fixed, but programmable, the flexibility will, of course, be even greater, since adaptation will then be possible via the program. If the input and output levels of the processor change because a new technology is used, the new voltage levels of the matching circuits will be adapted via the program.

The invention and advantageous developments will now be described in more detail with reference to the accompanying drawings, in which:

FIG. 1 is a schematic plan view of a typical mount for a monolithic integrated circuit according to the prior art;

FIG. 2 is a schematic plan view of a typical mount for a hybrid circuit according to the prior art;

FIG. 3 is a schematic plan view of a mount according to the invention for a lateral arrangement of a first and a second functional unit;

FIG. 4 is a schematic plan view of a mount according to the invention for a stacked arrangement of the first and second functional units;

FIG. 5 is a schematic plan view of a mount according to the invention for a combination of a stacked arrangement and a lateral arrangement;

FIG. 6 is a schematic plan view of a mount according to the invention in which all contacts of the first and second functional units are first connected to a passive carrier; and

FIG. 7 is a schematic cross-sectional view of a mount roughly according to FIG. 6, with the external terminals defined by an array of solder pads.

Referring to Fig. i, there is shown a schematic plan view of the typical arrangement of a monolithic integrated circuit 1 in a mount according to the prior art. The mount is generally a molded plastic package, whose outline is represented by a line 2. The carrier of the monolithic integrated circuit 1 is, as a rule, a flat metal stamping 3, the so-called frame, which, on the one hand, provides the through connections for the contact pads of the monolithic integrated circuit through the plastic package and, on the other hand, contains a platform 4 for receiving the monolithic integrated circuit i. As a rule, this platform is connected to an external ground pin. The contact pads of monolithic integrated circuit 1 are connected to the associated inner leads of frame 3 by bond wires. All external leads to monolithic integrated circuit 1 run via frame 3.

FIG. 2 shows a schematic plan view of a prior-art hybrid circuit. The hybrid circuit consists of two monolithic integrated circuits 5, 6. If the carrier is again a frame 3 with a platform 4, the two monolithic integrated circuits are arranged on this platform side by side. Contact is made to the monolithic integrated circuits 5, 6 via wire bonds which run either to the associated leads of frame 3 or directly from circuit to circuit. In some cases, use is made of a stacked structure, in which the smaller circuit is cemented onto the larger one. The smaller circuit is generally a memory circuit or a circuit with specific components, such as capacitors, coils, filters, etc.

Hybrid circuits are usually employed where subcircuits with different basic functions interact, for example an analog circuit and a digital circuit, possibly in conjunction with different memory types. Thus, the optimum technology is available for each circuit. In this manner it is also possible to combine products of different manufacturers. Mounts for hybrid circuits may also be entire printed circuit boards, to which connections are also generally made by wire bonding. The individual circuits and the wire bonds on the board are then protected by a plastic enclosure.

FIG. 3 is a schematic plan view of a mount according to the invention with a lateral arrangement of a first and a second functional unit 7, 8. The lateral arrangement of the two monolithic integrated functional units 7, 8 is relatively similar to the side-by-side arrangement of the two monolithic integrated circuits 5, 6 of FIG. 2. The difference lies in the fact that in FIG. 3, all external contacts are only connected to the first functional unit 7 and that the second functional unit 8 only has connections to the first functional unit 7. The common ground connection via platform 4 represents an exception. FIG. 3 already shows in the schematic representation that if a frame 3 is used, this mount is limited to relatively few external leads, because the wire bonds allow only a limited bonding geometry, and compensation by the design of the internal frame leads is only partially possible. A certain remedy is provided by the stacked arrangement shown in FIG. 4.

In the schematic stacked arrangement of FIG. 4, comprising two or more subcircuits on a frame platform 4, a central arrangement roughly as in FIG. 1 is preserved, so that all inner contacts of frame 3 can be easily reached from the edge of the first functional unit 7 via bond wires. Because of the stacked arrangement, the first functional unit 7 is allotted a carrier function for the second functional unit 8. This requires, of course, that the chip area of the first functional unit 7 is substantially greater than that of the second functional unit 8. The package outline or the border of the plastic enclosure is represented by the line 2.

FIG. 5 shows schematically an embodiment of a combination of a stacked arrangement and a lateral arrangement on a frame platform 4. The stacked arrangement approximately corresponds to FIG. 4, and the lateral arrangement to FIG. 3. The first functional unit 7 supports the second functional unit 8 and is connected laterally to a further, second functional or auxiliary unit 9 disposed on the common frame platform. All connections to the outside world go only via the first functional unit 7. The unit 9 may be a memory module, for example. Whether its connections to the second functional unit 8 are made directly by bond wires or indirectly via the first functional unit 7 will depend primarily on the spatial conditions. The package outline or the border of the plastic enclosure is represented by the line 2.

FIG. 6 is a schematic plan view of an embodiment of the mount in which the problem of inadequate accessibility of the external connections 30 from the first functional unit 7 is solved by the lateral arrangement of the first and second functional units 7, 8. An insulating carrier i0, consisting, for example, of a ceramic body with an interconnection plane Ii deposited on its surface, supports the first and second functional units 7, 8. The interconnection plane II may consist of several, mutually isolated layers of wiring to form all interconnections 12, 13, 14, 15, 16, 17 and associated contact areas 20. By means of wires bonds 40, connections are made from the first and second functional units 7, 8 to the contact areas 20 of the interconnections. The interconnections are isolated from each other and from the surface, and may therefore cross arbitrarily or pass below the first or second functional unit 7, 8; compare, for example, the crossover of interconnections 15 and 16, and the interconnection 17, which runs below the second functional unit 8. In this manner, all external terminals 30 of the mount can be easily reached from the first functional unit 7. Carrier 10 is also connected to the external terminals 30, or the latter were embedded in the carrier already during its manufacture. The whole structure is surrounded by a plastic enclosure, whose outline is represented by the dash-dotted line 2.

FIG. 7 shows a cross-sectional diagram of a further mount comprising a carrier 10 and a lateral arrangement of the first and second functional units 7, 8. The arrangement is roughly similar to that of FIG. 6. It differs from FIG. 6 in that the external terminals are defined by an array of solder pads 35. This arrangement will be used where the number of external terminals is so high that with a linear arrangement of terminals along the edges, the spacing becomes too small. Each of the solder pads 35 is connected to a via hole 36, which provides the electrical connection to interconnection plane ii. In the side view of FIG. 7, the wire bonds 40 from the first and second functional units 7, 8 to the interconnection plane Ii are clearly visible.

With the division into a first and a second functional unit, the invention is, of course, not limited to the use of monolithic integrated circuits. If appropriate, other manufacturing processes may be used for the individual subcircuits. What is important is that from outside, an electrically constant performance of the processing device is ensured, which is achieved by masking the processing device proper by means of a first functional unit having constant electrical parameters. 

1. A mount containing a programmable electronic processing device, particularly a microprocessor, which is divided into at least a first functional unit (7) and a second functional unit (8) which represent separate, particularly monolithic integrated, components, characterized in that that the first functional unit (7) defines all input and output interfaces of the processing device with respect to their electrical properties, all essential connections of the second functional unit (8) are accessible from outside only via the first functional unit (7), with direct accesses being normally, and first functional unit (7) comprises matching circuits which serve to electrically adapt the connections of the second functional unit (8) to the external conditions.
 2. A mount as claimed in claim 1, characterized in that at first the mount is bare or contains only a portion of the programmable electronic processing device, and that the mount so designed that the remaining portion or the remaining portions of the processing device can be incorporated later.
 3. A mount as claimed in claim 2, characterized in that the portion contained in the mount is regarded as forming part of the first functional unit (7).
 4. A mount as claimed in claim 1, characterized in that in at least one of the matching circuits, a change of a voltage level takes place.
 5. A mount as claimed in claim 4, characterized in that at least one supply terminal of the second functional unit (8) is fed via the first functional unit (7), in which case the matching circuit includes a voltage regulator.
 6. A mount as claimed in claim 1, characterized in that in at least one of the matching circuits, a change of a current level takes place.
 7. A mount as claimed in claim 1, characterized in that in at least one of the matching circuits, a conversion from a serial data stream to a parallel data stream or from a parallel data stream to a serial data stream takes place.
 8. A mount as claimed in claim 1, characterized in that in at least one of the matching circuits, incoming or outgoing data are temporarily stored.
 9. A mount as claimed in claim 1, characterized in that at least one of the matching circuits is programmable in terms of its electrical properties.
 10. A mount as claimed in claim 9, characterized in that for at least one of the matching circuits, a measurement mode is programmable.
 11. A mount as claimed in claim 10, characterized in that in the measurement mode for at least one of the matching circuits, a direct signal path from an external connection of the mount to a connection of the second functional unit (8) can be switched through by means of the program, with the indirect signal path via the matching circuit being off. 